I was just wondering why, how osu evaluate your pp.... because im shocked mrekk got 2k pp on his best performance but couldn't get #1 in rankings...any specific Information?

are we looking at the same rankings

edit: oh dear god this got moved i got scared

anyways, to put it simply: just cause someone got a high pp number doesn't mean they got the best score, probably cause they either missed, and that influences the score on the map they did, i thought you were referring to this page, so my apologies for the weird confusion in my original response

What the reply above implies but fails to state directly is that beatmap leaderboards are ordered by total score and not by pp.

pp leaderboards for beatmaps are a relatively recurring feature request that we may consider at some later date.